Maple syrup urine disease (MSUD), which gets its name from the odor of the affected baby’s urine, is a serious metabolic disorder that affects the way amino acids isoleucine, leucine, and valine are broken down. When these amino acids are not used to build up proteins, they are broken down and used for energy by an enzyme complex (enzymes are typically proteins) called branched-chain α-ketoacid dehydrogenase complex. Individuals with MSUD have a mutation for one of the proteins that make up this complex, resulting in a high build up of these amino acids in the body that can degenerate brain cells or even lead to death if not treated. MSUD is a recessive disorder and it generally occurs in 1 in 180,000 babies, but in some populations such as children of Amish, Mennonite, or Jewish descent the prevalence is higher. Symptoms for the disease may occur within 3-4 days after birth: baby will have sweet-smelling urine, exhibit loss of appetite, or be fussy. Therapy involves monitoring and restricting the patient’s diet to prevent brain damage. That means babies have to take a special formula that doesn’t contain isoleucine, leucine, or valine and adults with the disease must avoid foods high in protein like meat, nuts, and eggs.
For more information, visit this link: http://learn.genetics.utah.edu/content/disorders/whataregd/msud/